System and method for transmitting a signal

ABSTRACT

A system and method for transmitting a signal are disclosed herein. In one embodiment, the system and method are configured to perform: transmitting one or more synchronization signals using an anchor carrier with a first frequency location; and transmitting a system information block using a non-anchor carrier with a second frequency location that is different from the first frequency location.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation application of U.S.application Ser. No. 16/727,803 entitled “SYSTEM AND METHOD FORTRANSMITTING A SIGNAL,” filed on Dec. 26, 2019, which is a continuationof PCT international application PCT/CN2017/092805, entitled “SYSTEM ANDMETHOD FOR TRANSMITTING A SIGNAL,” filed on Jul. 13, 2017, which isexpressly incorporated by reference herein in its entirety.

TECHNICAL FIELD

The disclosure relates generally to wireless communications and, moreparticularly, to systems and methods to transmit a signal.

BACKGROUND

In accordance with rapid developments and increasing needs of theInternet of Things (IoT), a new radio interface, a Narrowband Internetof Things (NB-IoT), has been proposed by the 3^(rd) GenerationPartnership Project (3GPP). The NB-IoT is aimed to enhance existingGlobal System for Mobile Communications (GSM) and Long-Term Evolution(LTE) networks to better serve IoT uses or applications. Improved indoorcoverage, support for massive number of low throughput end devices, lowdelay sensitivity, ultra-low device cost, coverage extension, batterylifetime extension, and backward compatibility are some exemplaryobjectives of the NB-IoT.

Generally, in a wireless communication system adopting the NB-IoT(hereinafter “NB-IoT system”), a user equipment device (UE) camps in acell of a base station (BS) by performing a cell acquisition process.Such a cell acquisition process is typically performed when the UE isfirst switched on. Subsequently, the UE synchronizes with the cell, andthen retrieves various significant configuration information (e.g., adownlink bandwidth, system frame number, etc.) of the cell to finish theacquisition process. In existing NB-IoT systems, the UE synchronizeswith the cell by receiving primary and secondary synchronizationsignals, and retrieves the various significant configuration informationby reading a received Master Information Block (MIB) and at least areceived initial System Information Block (SIB1).

More particularly, in existing NB-IoT systems, the primary and secondarysynchronization signal (collectively referred to as “synchronizationsignals”), and the MIB and SIB1 (collectively referred to as “publicsignals”) are all required to be transmitted (e.g., modulated) on asingle carrier, typically known as an “anchor carrier,” from the BS tothe UE. Such a requirement of using a single carrier may encountervarious issues such as, for example, a substantially reduced amount ofavailable resources (e.g., a number of frames) on the anchor carrier,delayed reception of downlink control information and/or data whentransmitted on the anchor carrier, etc. Thus, existing methods in theNB-IoT system to transmit the synchronization signals and public signalsare not entirely satisfactory.

SUMMARY OF THE INVENTION

The exemplary embodiments disclosed herein are directed to solving theissues relating to one or more of the problems presented in the priorart, as well as providing additional features that will become readilyapparent by reference to the following detailed description when takenin conjunction with the accompany drawings. In accordance with variousembodiments, exemplary systems, methods, devices and computer programproducts are disclosed herein. It is understood, however, that theseembodiments are presented by way of example and not limitation, and itwill be apparent to those of ordinary skill in the art who read thepresent disclosure that various modifications to the disclosedembodiments can be made while remaining within the scope of theinvention.

In one embodiment, a method includes: transmitting one or moresynchronization signals using an anchor carrier with a first frequencylocation; and transmitting a system information block using a non-anchorcarrier with a second frequency location that is different from thefirst frequency location.

In a further embodiment, a method includes: receiving one or moresynchronization signals modulated on an anchor carrier with a firstfrequency location; and receiving a system information block modulatedon a non-anchor carrier with a second frequency location that isdifferent from the first frequency location.

In another embodiment, a communication node includes: a transmitterconfigured to: transmit one or more synchronization signals using ananchor carrier with a first frequency location; and transmit a systeminformation block using a non-anchor carrier with a second frequencylocation that is different from the first frequency location.

In yet another embodiment, a communication node, includes: a receiverconfigured to: receive one or more synchronization signals modulated onan anchor carrier with a first frequency location; receive a systeminformation block modulated on a non-anchor carrier with a secondfrequency location that is different from the first frequency location.

BRIEF DESCRIPTION OF THE DRAWINGS

Various exemplary embodiments of the invention are described in detailbelow with reference to the following Figures. The drawings are providedfor purposes of illustration only and merely depict exemplaryembodiments of the invention to facilitate the reader's understanding ofthe invention. Therefore, the drawings should not be considered limitingof the breadth, scope, or applicability of the invention. It should benoted that for clarity and ease of illustration these drawings are notnecessarily drawn to scale.

FIG. 1 illustrates an exemplary cellular communication network in whichtechniques disclosed herein may be implemented, in accordance with anembodiment of the present disclosure.

FIG. 2 illustrates block diagrams of an exemplary base station and auser equipment device, in accordance with some embodiments of thepresent disclosure.

FIG. 3A illustrates exemplary frame structures of an anchor carrier anda non-anchor carrier, respectively, in accordance with some embodimentsof the present disclosure.

FIGS. 3B, 3C, and 3D each illustrates a plurality of frequency locationoptions of the non-anchor carrier of FIG. 3A when used in a standalonemode and a non-standalone mode, respectively, in accordance with someembodiments of the present disclosure.

FIG. 4 illustrates exemplary frame structures of an anchor carrier and anon-anchor carrier, respectively, in accordance with some embodiments ofthe present disclosure.

FIG. 5 illustrates exemplary frame structures of an anchor carrier and anon-anchor carrier, respectively, in accordance with some embodiments ofthe present disclosure.

FIG. 6 illustrates exemplary frame structures of an anchor carrier and anon-anchor carrier, respectively, in accordance with some embodiments ofthe present disclosure.

FIG. 7 illustrates exemplary frame structures of an anchor carrier and anon-anchor carrier, respectively, in accordance with some embodiments ofthe present disclosure.

FIG. 8 illustrates exemplary frame structures of an anchor carrier and anon-anchor carrier, respectively, in accordance with some embodiments ofthe present disclosure.

FIG. 9 illustrates exemplary frame structures of an anchor carrier and anon-anchor carrier, respectively, in accordance with some embodiments ofthe present disclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Various exemplary embodiments of the invention are described below withreference to the accompanying figures to enable a person of ordinaryskill in the art to make and use the invention. As would be apparent tothose of ordinary skill in the art, after reading the presentdisclosure, various changes or modifications to the examples describedherein can be made without departing from the scope of the invention.Thus, the present invention is not limited to the exemplary embodimentsand applications described and illustrated herein. Additionally, thespecific order or hierarchy of steps in the methods disclosed herein aremerely exemplary approaches. Based upon design preferences, the specificorder or hierarchy of steps of the disclosed methods or processes can bere-arranged while remaining within the scope of the present invention.Thus, those of ordinary skill in the art will understand that themethods and techniques disclosed herein present various steps or acts ina sample order, and the invention is not limited to the specific orderor hierarchy presented unless expressly stated otherwise.

FIG. 1 illustrates an exemplary wireless communication network 100 inwhich techniques disclosed herein may be implemented, in accordance withan embodiment of the present disclosure. In the following discussion,the wireless communication network 100 may be a NB-IoT network, which isherein referred to as “network 100.” Such an exemplary network 100includes a base station 102 (hereinafter “BS 102”) and a user equipmentdevice 104 (hereinafter “UE 104”) that can communicate with each othervia a communication link 110 (e.g., a wireless communication channel),and a cluster of notional cells 126, 130, 132, 134, 136, 138 and 140overlaying a geographical area 101. In FIG. 1 , the BS 102 and UE 104are contained within a respective geographic boundary of cell 126. Eachof the other cells 130, 132, 134, 136, 138 and 140 may include at leastone base station operating at its allocated bandwidth to provideadequate radio coverage to its intended users.

For example, the BS 102 may operate at an allocated channel transmissionbandwidth to provide adequate coverage to the UE 104. The BS 102 and theUE 104 may communicate via a downlink radio frame 118, and an uplinkradio frame 124 respectively. Each radio frame 118/124 may be furtherdivided into sub-frames 120/127 which may include data symbols 122/128.In the present disclosure, the BS 102 and UE 104 are described herein asnon-limiting examples of “communication nodes,” generally, which canpractice the methods disclosed herein. Such communication nodes may becapable of wireless and/or wired communications, in accordance withvarious embodiments of the invention.

FIG. 2 illustrates a block diagram of an exemplary wirelesscommunication system 200 for transmitting and receiving wirelesscommunication signals, e.g., OFDM/OFDMA signals, in accordance with someembodiments of the invention. The system 200 may include components andelements configured to support known or conventional operating featuresthat need not be described in detail herein. In one exemplaryembodiment, system 200 can be used to transmit and receive data symbolsin a wireless communication environment such as the wirelesscommunication environment 100 of FIG. 1 , as described above.

System 200 generally includes a base station 202 (hereinafter “BS 202”)and a user equipment device 204 (hereinafter “UE 204”). The BS 202includes a BS (base station) transceiver module 210, a BS antenna 212, aBS processor module 214, a BS memory module 216, and a networkcommunication module 218, each module being coupled and interconnectedwith one another as necessary via a date communication bus 220. The UE204 includes a UE (user equipment) transceiver module 230, a UE antenna232, a UE memory module 234, and a UE processor module 236, each modulebeing coupled and interconnected with one another as necessary via adata communication bus 240. The BS 202 communicates with the UE 204 viaa communication channel 250, which can be any wireless channel or othermedium known in the art suitable for transmission of data as describedherein.

As would be understood by persons of ordinary skill in the art, system200 may further include any number of modules other than the modulesshown in FIG. 2 . Those skilled in the art will understand that thevarious illustrative blocks, modules, circuits, and processing logicdescribed in connection with the embodiments disclosed herein may beimplemented in hardware, computer-readable software, firmware, or anypractical combination thereof. To clearly illustrate thisinterchangeability and compatibility of hardware, firmware, andsoftware, various illustrative components, blocks, modules, circuits,and steps are described generally in terms of their functionality.Whether such functionality is implemented as hardware, firmware, orsoftware depends upon the particular application and design constraintsimposed on the overall system. Those familiar with the conceptsdescribed herein may implement such functionality in a suitable mannerfor each particular application, but such implementation decisionsshould not be interpreted as limiting the scope of the presentinvention.

In accordance with some embodiments, the UE transceiver 230 may bereferred to herein as an “uplink” transceiver 230 that includes a RFtransmitter and receiver circuitry that are each coupled to the antenna232. A duplex switch (not shown) may alternatively couple the uplinktransmitter or receiver to the uplink antenna in time duplex fashion.Similarly, in accordance with some embodiments, the BS transceiver 210may be referred to herein as a “downlink” transceiver 210 that includesRF transmitter and receiver circuitry that are each coupled to theantenna 212. A downlink duplex switch may alternatively couple thedownlink transmitter or receiver to the downlink antenna 212 in timeduplex fashion. The operations of the two transceivers 210 and 230 arecoordinated in time such that the uplink receiver is coupled to theuplink antenna 232 for reception of transmissions over the wirelesstransmission link 250 at the same time that the downlink transmitter iscoupled to the downlink antenna 212. Preferably there is close timesynchronization with only a minimal guard time between changes in duplexdirection.

The UE transceiver 230 and the base station transceiver 210 areconfigured to communicate via the wireless data communication link 250,and cooperate with a suitably configured RF antenna arrangement 212/232that can support a particular wireless communication protocol andmodulation scheme. In some exemplary embodiments, the UE transceiver 210and the base station transceiver 210 are configured to support industrystandards such as the Long Term Evolution (LTE) and emerging 5Gstandards, and the like. It is understood, however, that the inventionis not necessarily limited in application to a particular standard andassociated protocols. Rather, the UE transceiver 230 and the basestation transceiver 210 may be configured to support alternate, oradditional, wireless data communication protocols, including futurestandards or variations thereof.

In accordance with various embodiments, the BS 202 may be an evolvednode B (eNB), a serving eNB, a target eNB, a femto station, or a picostation, for example. In some embodiments, the UE 204 may be embodied invarious types of user devices such as a mobile phone, a smart phone, apersonal digital assistant (PDA), tablet, laptop computer, wearablecomputing device, etc. The processor modules 214 and 236 may beimplemented, or realized, with a general purpose processor, a contentaddressable memory, a digital signal processor, an application specificintegrated circuit, a field programmable gate array, any suitableprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof, designed to perform thefunctions described herein. In this manner, a processor may be realizedas a microprocessor, a controller, a microcontroller, a state machine,or the like. A processor may also be implemented as a combination ofcomputing devices, e.g., a combination of a digital signal processor anda microprocessor, a plurality of microprocessors, one or moremicroprocessors in conjunction with a digital signal processor core, orany other such configuration.

Furthermore, the steps of a method or algorithm described in connectionwith the embodiments disclosed herein may be embodied directly inhardware, in firmware, in a software module executed by processormodules 214 and 236, respectively, or in any practical combinationthereof. The memory modules 216 and 234 may be realized as RAM memory,flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a harddisk, a removable disk, a CD-ROM, or any other form of storage mediumknown in the art. In this regard, memory modules 216 and 234 may becoupled to the processor modules 210 and 230, respectively, such thatthe processors modules 210 and 230 can read information from, and writeinformation to, memory modules 216 and 234, respectively. The memorymodules 216 and 234 may also be integrated into their respectiveprocessor modules 210 and 230. In some embodiments, the memory modules216 and 234 may each include a cache memory for storing temporaryvariables or other intermediate information during execution ofinstructions to be executed by processor modules 210 and 230,respectively. Memory modules 216 and 234 may also each includenon-volatile memory for storing instructions to be executed by theprocessor modules 210 and 230, respectively.

The network communication module 218 generally represents the hardware,software, firmware, processing logic, and/or other components of thebase station 202 that enable bi-directional communication between basestation transceiver 210 and other network components and communicationnodes configured to communication with the base station 202. Forexample, network communication module 218 may be configured to supportinternet or WiMAX traffic. In a typical deployment, without limitation,network communication module 218 provides an 802.3 Ethernet interfacesuch that base station transceiver 210 can communicate with aconventional Ethernet based computer network. In this manner, thenetwork communication module 218 may include a physical interface forconnection to the computer network (e.g., Mobile Switching Center(MSC)).

Referring again to FIG. 1 , when the UE 104 performs the cellacquisition process to camp in the cell 126 of the BS 102, the UE 104receives respective synchronization signals and public signals forsynchronization and configurations purposes, respectively. The existingNB-IoT system requires the synchronization signals and public signals tobe transmitted on a single carrier, which causes various issues asdescribed above.

The present disclosure provides various embodiments of systems andmethods to transmit the synchronization signals and at least part of thepublic signals on respective different carriers, which are hereinreferred to as “anchor carrier” and “non-anchor carrier,” respectively.In particular, when a carrier is used to transmit the synchronizationsignals, such a carrier is referred to as an anchor carrier; and when acarrier is not used to transmit the synchronization signals, such acarrier is referred to as a non-anchor carrier. In some embodiments, theanchor carrier and the non-anchor carrier share a same carrierbandwidth, but have respective different frequency locations, which maybe pre-defined by a protocol of the network 100. In some otherembodiments, the protocol may define the frequency location of theanchor carrier and, based on the frequency location of the anchorcarrier, provide a plurality of options, each of which corresponds to arespective available frequency location for the non-anchor carrier. Insome embodiments, a signal transmitted on the anchor carrier mayindicate which of the plurality of options is the frequency location ofthe non-anchor carrier. Accordingly, upon receiving the indicationcontained in the signal transmitted on the anchor carrier, the UE 104may follow the indication to retrieve various signals transmitted on thenon-anchor carrier. By separating the synchronization signals and atleast part of the public signals to be transmitted on respectivedifferent carriers, various advantages may be provided such as, forexample, substantially reduced reception delay on the downlink controlinformation and/or data when transmitted on the anchor carrier,substantially reduced power consumption to receive the downlink controlinformation and/or data when transmitted on the anchor carrier, etc.

FIG. 3A illustrates exemplary frame structures of an anchor carrier 310and a non-anchor carrier 330, respectively, in accordance with someembodiments of the present disclosure. In some embodiments, when theanchor carrier 310 and the non-anchor carrier 330 are used in the NB-IoTsystem, the anchor carrier 310 and the non-anchor carrier 330 share asame carrier bandwidth “B” (e.g., 180 kHz) along a frequency domain. Insome embodiments, the anchor carrier 310 and the non-anchor carrier 330may occupy respective different frequency ranges. Alternatively stated,respective frequency locations of the anchor carrier 310 and thenon-anchor carrier 330 may be spaced from each other by one or morecarrier bandwidths B, which will be discussed in further detail below.

In the illustrated embodiment of FIG. 3A, the anchor carrier 310includes frames 310-1, 310-2, 310-3, and 310-4 coupled from one toanother along a time domain; and the non-anchor carrier 330 includesframes 330-1, 330-2, 330-3, and 330-4 coupled from one to another alongthe time domain. In some embodiments, each frame of the anchor carrier310 correspond to a respective frame of the non-anchor carrier 330 alongthe time domain, that is, sharing a same time period. For example, theframe 310-1 shares a same time period with the frame 330-1; the frame310-2 shares a same time period with the frame 330-2; the frame 310-3shares a same time period with the frame 330-3; and the frame 310-4shares a same time period with the frame 330-4. Although only fourframes are illustrated in each of the anchor carrier 310 and thenon-anchor carrier 330, it is understood that each of the anchor carrier310 and the non-anchor carrier 330 may have any desired number of frameswhile remaining within the scope of the present disclosure. For example,the anchor carrier 310 may include plural sets, each of which consistsof the frames 310-1, 310-2, 310-3, and 310-4; and the non-anchor carrier330 may include plural set, each of which consists of the frames 330-1,330-2, 330-3, and 330-4, wherein the respective sets of the anchorcarrier 310 and the non-anchor carrier 330 are periodically repeated. Insome embodiments, such a periodic repetition of respective frames withinthe anchor carrier and non-anchor carrier may be applicable for theexamples provided in FIGS. 4, 5, 6, 7, 8, and 9 , so that discussions ofthe periodic repetition of respective frames will not be repeated below.

In some embodiments, each of the respective frames of the anchor carrier310 and the non-anchor carrier 330 includes 10 sub-frames, each of whichis associated with a sub-frame index #, e.g., 0, 1, 2, 3, 4, 5, 6, 7, 8,or 9. Although not shown, it is understood by persons of ordinary skillin the art that each sub-frame of the anchor carrier 310 and thenon-anchor carrier 330 has a plurality of symbols (e.g., 14 symbols),each of which may carry a sequence value or data. Further, in theillustrated embodiment of FIG. 3A, the synchronization signals,including the primary synchronization signal (PSS) and the secondarysynchronization signal (SSS), and part of the public signals, includingthe Master Information Block (MIB), are transmitted on the anchorcarrier 310; and part of the public signals, including the initialSystem Information Block (SIB1), are transmitted on the non-anchorcarrier 330. In some embodiments, in the NB-IoT system, the PSS, theSSS, the MIB, and the SIB1 are also referred to as “narrowband PSS(NPSS),” “narrowband SSS (NSSS),” “MIB-narrowband (MIB-NB),” and“SIB1-narrowband (SIB1-NB),” respectively. For purpose of consistency,the terms “PSS,” “SSS,” “MIB,” and “SIB1” are consistently used in thefollowing discussions.

More specifically, in some embodiments, the PSS is transmitted onsub-frame #0 of the frame 310-1, sub-frame #0 of the frame 310-2,sub-frame #0 of the frame 310-3, and sub-frame #0 of the frame 310-4;the SSS is transmitted on sub-frame #5 of the frame 310-1, and sub-frame#5 of the frame 310-3; and the MIB is transmitted on sub-frame #5 of theframe 310-2, and sub-frame #5 of the frame 310-4. The SIB1 can betransmitted on sub-frame #0 of the frame 330-1, and sub-frame #0 of theframe 330-3. For clarity of illustration, the respective sub-frame(s)used to transmit the PSS, the SSS, the MIB, and the SIB1 are filled witha diagonal stripe pattern, a dotted pattern, a vertical stripe pattern,and a horizontal stripe pattern, respectively. It is noted that theanchor carrier 310 and the non-anchor carrier 330 may be used in theNB-IoT system utilizing a time domain duplex (TDD) transmission mode,which causes the sub-frames used by the SIB1 to be respectively alignedwith at least part of the sub-frames used by the PSS along the timedomain.

As mentioned above, in accordance with some embodiments of the presentdisclosure, one of the signals transmitted on the anchor carrier mayindicate a frequency location of the non-anchor carrier from a pluralityof frequency location options of the non-anchor carrier, wherein such aplurality of frequency location locations of the non-anchor carrier arepre-defined by the protocol of the NB-IoT system. FIGS. 3B, 3C, and 3Deach provides two examples of such a plurality of frequency locationoptions of the non-anchor carrier when the NB-IoT system operates undera standalone mode and a non-standalone mode, respectively. As understoodby persons of ordinary skill in the art, when the NB-IoT system operatesunder the standalone mode, the anchor carrier 310 and the non-anchorcarrier 330 each resides within Global System for Mobile Communication(GSM) frequencies; and when the NB-IoT system operates under thenon-standalone mode, the anchor carrier 310 and the non-anchor carrier330 each resides within Long-Term Evolution (LTE) frequencies.

Referring first to example 350 of FIG. 3B in which the NB-IoT systemoperates under the standalone mode, a plurality of options 350-1, 350-2,350-3, and 350-4 of the frequency location of the non-anchor carrier 330are provided with respect to frequency location 350-0 of the anchorcarrier 310. As shown, the frequency location 350-1 of the non-anchorcarrier 330 is positively spaced apart from the frequency location 350-0of the anchor carrier 310 by 2 carrier bandwidths (i.e., 2×B); thefrequency location 350-2 of the non-anchor carrier 330 is positivelyspaced apart from the frequency location 350-0 of the anchor carrier 310by 1 carrier bandwidth (i.e., 1×B); the frequency location 350-3 of thenon-anchor carrier 330 is negatively spaced apart from the frequencylocation 350-0 of the anchor carrier 310 by 1 carrier bandwidth (i.e.,−1×B); and the frequency location 350-4 of the non-anchor carrier 330 isnegatively spaced apart from the frequency location 350-0 of the anchorcarrier 310 by 2 carrier bandwidths (i.e., −2×B).

In example 352 of FIG. 3B in which the NB-IoT system operates under thenon-standalone mode, a plurality of options 352-1, 352-2, 352-3, and352-4 of the frequency location of the non-anchor carrier 330 areprovided with respect to frequency location 352-0 of the anchor carrier310. As shown, the frequency location 352-1 of the non-anchor carrier330 is positively spaced apart from the frequency location 352-0 of theanchor carrier 310 by 12 carrier bandwidths (i.e., 12×B); the frequencylocation 352-2 of the non-anchor carrier 330 is positively spaced apartfrom the frequency location 352-0 of the anchor carrier 310 by 6 carrierbandwidths (i.e., 6×B); the frequency location 352-3 of the non-anchorcarrier 330 is negatively spaced apart from the frequency location 352-0of the anchor carrier 310 by 6 carrier bandwidths (i.e., −6×B); and thefrequency location 352-4 of the non-anchor carrier 330 is negativelyspaced apart from the frequency location 352-0 of the anchor carrier 310by 12 carrier bandwidths (i.e., −12×B).

According to the examples 350 and 352 provided in FIG. 3B, it is notedthat when the NB-IoT system operates under the standalone mode, there isa first carrier bandwidth spacing between respective frequency locationsof any two adjacent carriers (e.g., between respective frequencylocations of one of the options of the non-anchor carrier 330 and theanchor carrier 310, between respective frequency locations of twoadjacent options, for example, 350-1 and 350-2, of the non-anchorcarrier 330, etc.); and when the NB-IoT system operates under thenon-standalone mode, there is a second carrier bandwidth spacing betweenrespective frequency locations of any two adjacent carriers (e.g.,between respective frequency locations of one of the options of thenon-anchor carrier 330 and the anchor carrier 310, between respectivefrequency locations of two adjacent options, for example, 352-1 and352-2, of the non-anchor carrier 330, etc.). In some embodiments, thefirst carrier bandwidth spacing (e.g., B) is different from the secondcarrier bandwidth spacing (e.g., 6B).

In accordance with the illustrated embodiment of FIG. 3A, the MIB,transmitted using the anchor carrier 310 on the frequency location 350-0or 352-0, may indicate the frequency location of the non-anchor carrier330 by selecting one from either the plurality of frequency locationoptions 350-1 to 350-4 or the plurality of frequency location options352-1 to 352-4. As such, after the UE 104 (FIG. 1 ) receives and thenread the MIB that is transmitted on the anchor carrier 310, the UE 104can know using which frequency location to receive the SIB1 that istransmitted on the non-anchor carrier 330.

FIGS. 3C and 3D each provides other exemplary “distributions” of thefrequency location of the non-anchor carrier 330 with respect to arespective frequency location of the anchor carrier 310 when the NB-IoTsystem switches to operate between the standalone mode andnon-standalone mode, respectively. Since FIGS. 3C and 3D aresubstantially similar to FIG. 3B, discussions of FIGS. 3C and 3D arebriefly provided as follows.

In example 354 of FIG. 3C in which the NB-IoT system operates under thestandalone mode, a plurality of options 354-1, 354-2, 354-3, and 354-4of the frequency location of the non-anchor carrier 330 are providedwith respect to frequency location 354-0 of the anchor carrier 310. Asshown, the frequency location 354-1 of the non-anchor carrier 330 ispositively spaced apart from the frequency location 354-0 of the anchorcarrier 310 by 7 carrier bandwidths (i.e., 7×B); the frequency location354-2 of the non-anchor carrier 330 is positively spaced apart from thefrequency location 354-0 of the anchor carrier 310 by 1 carrierbandwidth (i.e., 1×B); the frequency location 354-3 of the non-anchorcarrier 330 is negatively spaced apart from the frequency location 354-0of the anchor carrier 310 by 1 carrier bandwidth (i.e., −1×B); and thefrequency location 354-4 of the non-anchor carrier 330 is negativelyspaced apart from the frequency location 354-0 of the anchor carrier 310by 72 carrier bandwidths (i.e., −7×B).

In example 356 of FIG. 3C in which the NB-IoT system operates under thenon-standalone mode, a plurality of options 356-1, 356-2, 356-3, and356-4 of the frequency location of the non-anchor carrier 330 areprovided with respect to frequency location 356-0 of the anchor carrier310. As shown, the frequency location 356-1 of the non-anchor carrier330 is positively spaced apart from the frequency location 356-0 of theanchor carrier 310 by 12 carrier bandwidths (i.e., 12×B); the frequencylocation 356-2 of the non-anchor carrier 330 is positively spaced apartfrom the frequency location 356-0 of the anchor carrier 310 by 3 carrierbandwidths (i.e., 3×B); the frequency location 356-3 of the non-anchorcarrier 330 is negatively spaced apart from the frequency location 356-0of the anchor carrier 310 by 3 carrier bandwidths (i.e., −3×B); and thefrequency location 356-4 of the non-anchor carrier 330 is negativelyspaced apart from the frequency location 356-0 of the anchor carrier 310by 12 carrier bandwidths (i.e., −12×B).

According to the examples 354 and 356 provided in FIG. 3C, it is notedthat when the NB-IoT system operates under the standalone mode, thereare two respective different carrier bandwidth spacings (first andsecond carrier bandwidth spacings) between respective frequencylocations of any two adjacent carriers (e.g., between respectivefrequency locations of one of the options of the non-anchor carrier 330and the anchor carrier 310, between respective frequency locations oftwo adjacent options, for example, 354-1 and 354-2, of the non-anchorcarrier 330, etc.); and when the NB-IoT system operates under thenon-standalone mode, there are two respective different carrierbandwidth spacings (third and fourth carrier bandwidth spacings) betweenrespective frequency locations of any two adjacent carriers (e.g.,between respective frequency locations of one of the options of thenon-anchor carrier 330 and the anchor carrier 310, between respectivefrequency locations of two adjacent options, for example, 356-1 and356-2, of the non-anchor carrier 330, etc.). In some embodiments, thefirst (e.g., B), second (e.g., 6B), third (e.g., 3B), and fourth (e.g.,9B) carrier bandwidth spacings are different from one another.

In example 358 of FIG. 3D in which the NB-IoT system operates under thestandalone mode, a plurality of options 358-1, 358-2, 358-3, and 358-4of the frequency location of the non-anchor carrier 330 are providedwith respect to frequency location 358-0 of the anchor carrier 310. Asshown, the frequency location 358-1 of the non-anchor carrier 330 ispositively spaced apart from the frequency location 358-0 of the anchorcarrier 310 by 7 carrier bandwidths (i.e., 7×B); the frequency location358-2 of the non-anchor carrier 330 is positively spaced apart from thefrequency location 358-0 of the anchor carrier 310 by 1 carrierbandwidth (i.e., 1×B); the frequency location 358-3 of the non-anchorcarrier 330 is negatively spaced apart from the frequency location 358-0of the anchor carrier 310 by 1 carrier bandwidth (i.e., −1×B); and thefrequency location 358-4 of the non-anchor carrier 330 is negativelyspaced apart from the frequency location 358-0 of the anchor carrier 310by 7 carrier bandwidths (i.e., −7×B).

In example 360 of FIG. 3D in which the NB-IoT system operates under thenon-standalone mode, a plurality of options 360-1, 360-2, 360-3, and360-4 of the frequency location of the non-anchor carrier 330 areprovided with respect to frequency location 360-0 of the anchor carrier310. As shown, the frequency location 360-1 of the non-anchor carrier330 is positively spaced apart from the frequency location 360-0 of theanchor carrier 310 by 12 carrier bandwidths (i.e., 12×B); the frequencylocation 360-2 of the non-anchor carrier 330 is positively spaced apartfrom the frequency location 360-0 of the anchor carrier 310 by 6 carrierbandwidths (i.e., 6×B); the frequency location 360-3 of the non-anchorcarrier 330 is negatively spaced apart from the frequency location 360-0of the anchor carrier 310 by 6 carrier bandwidths (i.e., −6×B); and thefrequency location 360-4 of the non-anchor carrier 330 is negativelyspaced apart from the frequency location 360-0 of the anchor carrier 310by 12 carrier bandwidths (i.e., −12×B).

According to the examples 358 and 360 provided in FIG. 3D, it is notedthat when the NB-IoT system operates under the standalone mode, thereare respective different carrier bandwidth spacings (first and secondcarrier bandwidth spacings) between respective frequency locations ofany two adjacent carriers (e.g., between respective frequency locationsof one of the options of the non-anchor carrier 330 and the anchorcarrier 310, between respective frequency locations of two adjacentoptions, for example, 358-1 and 358-2, of the non-anchor carrier 330,etc.); and when the NB-IoT system operates under the non-standalonemode, there is a single carrier bandwidth spacing (third carrierbandwidth spacing) between respective frequency locations of any twoadjacent carriers (e.g., between respective frequency locations of oneof the options of the non-anchor carrier 330 and the anchor carrier 310,between respective frequency locations of two adjacent options, forexample, 360-1 and 360-2, of the non-anchor carrier 330, etc.). In someembodiments, each of the first and second carrier bandwidth spacings(e.g., B and 6B) may be different from or identical to the third carrierbandwidth spacing (e.g., 6B). In some alternative embodiments, when theNB-IoT system operates under the standalone mode, there may be a singlecarrier bandwidth spacing between respective frequency locations of anytwo adjacent carriers; and when the NB-IoT system operates under thenon-standalone mode, there may be respective different carrier bandwidthspacings between respective frequency locations of any two adjacentcarriers.

Similarly, in accordance with the illustrated embodiment of FIG. 3A, theMIB, transmitted using the anchor carrier 310 on the frequency location(e.g., 354-0, 356-0, 358-0, or 360-0), may indicate the frequencylocation of the non-anchor carrier 330 by selecting one from theplurality of corresponding frequency location options (e.g., 354-1 to354-4, 356-1 to 356-4, 358-1 to 358-4, or 360-1 to 360-4). As such,after the UE 104 (FIG. 1 ) receives and then read the MIB that istransmitted on the anchor carrier 310, the UE 104 can know using whichof the frequency locations to receive the SIB1 that is transmitted onthe non-anchor carrier 330.

FIG. 4 illustrates exemplary frame structures of an anchor carrier 410and a non-anchor carrier 430, respectively, in accordance with someembodiments of the present disclosure. Similarly, the anchor carrier 410and the non-anchor carrier 430 share the same carrier bandwidth “B”(e.g., 180 kHz) along the frequency domain. In some embodiments, theanchor carrier 410 and the non-anchor carrier 430 may occupy respectivedifferent frequency ranges. Alternatively stated, the anchor carrier 410and the non-anchor carrier 430 may be spaced from each other by one ormore carrier bandwidths B, which will be discussed in further detailbelow.

In the illustrated embodiment of FIG. 4 , the anchor carrier 410includes frames 410-1, 410-2, 410-3, and 410-4 coupled from one toanother along a time domain; and the non-anchor carrier 430 includesframes 430-1, 430-2, 430-3, and 430-4 coupled from one to another alongthe time domain. In some embodiments, each of the respective frames ofthe anchor carrier 410 and the non-anchor carrier 430 includes 10sub-frames, each of which is associated with a sub-frame index #, e.g.,0, 1, 2, 3, 4, 5, 6, 7, 8, or 9. Further, in the illustrated embodimentof FIG. 4 , the synchronization signals, including the PSS and the SSS,and part of the public signals, including the MIB, are transmitted onthe anchor carrier 410; and part of the public signals, including theSIB1, are transmitted on the non-anchor carrier 430.

More specifically, in some embodiments, the PSS is transmitted onsub-frame #0 of the frame 410-1, sub-frame #0 of the frame 410-2,sub-frame #0 of the frame 410-3, and sub-frame #0 of the frame 410-4;the SSS is transmitted on sub-frame #5 of the frame 410-1; and the MIBis transmitted on sub-frame #5 of the frame 410-2, and sub-frame #5 ofthe frame 410-4. The SIB1 can be transmitted on sub-frame #0 of theframe 430-1, sub-frame #0 of the frame 430-2, sub-frame #0 of the frame430-3, and sub-frame #0 of the frame 430-4. For clarity of illustration,the respective sub-frame(s) used to transmit the PSS, the SSS, the MIB,and the SIB1 are filled with a diagonal stripe pattern, a dottedpattern, a vertical stripe pattern, and a horizontal stripe pattern,respectively. It is noted that the anchor carrier 410 and the non-anchorcarrier 430 may be used in the NB-IoT system utilizing the TDDtransmission mode, which causes the sub-frames used by the SIB1 to berespectively aligned with at least part of the sub-frames used by thePSS along the time domain.

When compared to the frame structure of the non-anchor carrier 330 ofFIG. 3A, the frame structure of the non-anchor carrier 430 of FIG. 4includes more sub-frames that can be used to transmit the SIB. As such,when the BS 102 uses the frame structure of the non-anchor carrier 430of FIG. 4 to transmit the SIB1, the UE 104 may responsively spend lesstime decoding the SIB1; and when the BS 102 uses the frame structure ofthe non-anchor carrier 330 of FIG. 3A to transmit the SIB1, the UE 104may responsively spend more time decoding the SIB1. In some embodiments,based on the respective decoding requirements, the BS 102 may determinewhich of the frame structures between 330 and 430 for the use oftransmitting the SIB1. As a choice, the BS 102 may use the MIB toindicate which sub-frame(s) in the non-anchor carrier (330 or 430) hasbeen used to transmit the SIB1. For example, the MIB uses how many timesthe SIB1 is going to be repeatedly transmitted within a schedulingperiod to implicitly indicate which sub-frame(s) will be used totransmit the SIB1. In particular, when a number of times falls into afirst subset, the SIB1 is going to be transmitted using the sub-framesas shown in FIG. 3A; and when the number of times falls into a secondsubset, the SIB1 is going to be transmitted using the sub-frames asshown in FIG. 4 .

In accordance with the illustrated embodiment of FIG. 4 , neither thePSS, nor the SSS, nor the MIB, transmitted using the anchor carrier 410on a respective frequency location (not shown), indicates the frequencylocation of the non-anchor carrier 430. Instead, the frequency locationof the non-anchor carrier 430 with respect to the frequency location ofthe anchor carrier 410 may be pre-defined by the above-mentionedprotocol of the NB-IoT system. For example, when the NB-IoT systemoperates under the standalone mode, the frequency location of thenon-anchor carrier 430 may be pre-defined to be positively or negativelyspaced apart from the frequency location of the anchor carrier 410 by 1carrier bandwidth (i.e., 1×B or −1×B); and when the NB-IoT systemoperates under the non-standalone mode, the frequency location of thenon-anchor carrier 430 may be pre-defined to be positively or negativelyspaced apart from the frequency location of the anchor carrier 410 by 6carrier bandwidths (i.e., 6×B or −6×B).

FIG. 5 illustrates exemplary frame structures of an anchor carrier 510and a non-anchor carrier 530, respectively, in accordance with someembodiments of the present disclosure. Similarly, the anchor carrier 510and the non-anchor carrier 530 share the same carrier bandwidth “B”(e.g., 180 kHz) along the frequency domain. In some embodiments, theanchor carrier 510 and the non-anchor carrier 530 may occupy respectivedifferent frequency ranges. Alternatively stated, respective frequencylocations of the anchor carrier 510 and the non-anchor carrier 530 maybe spaced from each other by one or more carrier bandwidths B, whichwill be discussed in further detail below.

In the illustrated embodiment of FIG. 5 , the anchor carrier 510includes frames 510-1, 510-2, 510-3, and 510-4 coupled from one toanother along a time domain; and the non-anchor carrier 530 includesframes 530-1, 530-2, 530-3, and 530-4 coupled from one to another alongthe time domain. In some embodiments, each of the respective frames ofthe anchor carrier 510 and the non-anchor carrier 530 includes 10sub-frames, each of which is associated with a sub-frame index #, e.g.,0, 1, 2, 3, 4, 5, 6, 7, 8, or 9. Further, in the illustrated embodimentof FIG. 5 , the synchronization signals, including the PSS and the SSS,and part of the public signals, including the MIB, are transmitted onthe anchor carrier 510; and part of the public signals, including theSIB1, are transmitted on the non-anchor carrier 530.

More specifically, in some embodiments, the PSS is transmitted onsub-frame #0 of the frame 510-1, sub-frame #0 of the frame 510-2,sub-frame #0 of the frame 510-3, and sub-frame #0 of the frame 510-4;the SSS is transmitted on sub-frame #5 of the frame 510-1; and the MIBis transmitted on sub-frame #5 of the frame 510-2, sub-frame #5 of theframe 510-3, and sub-frame #5 of the frame 510-4. The SIB1 can betransmitted on sub-frame #0 of the frame 530-1, sub-frame #0 of theframe 530-2, sub-frame #0 of the frame 530-3, and sub-frame #0 of theframe 530-4. For clarity of illustration, the respective sub-frame(s)used to transmit the PSS, the SSS, the MIB, and the SIB1 are filled witha diagonal stripe pattern, a dotted pattern, a vertical stripe pattern,and a horizontal stripe pattern, respectively. It is noted that theanchor carrier 510 and the non-anchor carrier 530 may be used in theNB-IoT system utilizing the TDD transmission mode, which causes thesub-frames used by the SIB1 to be respectively aligned with at leastpart of the sub-frames used by the PSS along the time domain.

When compared to the frame structure of the anchor carrier 410 of FIG. 4, the frame structure of the anchor carrier 510 of FIG. 5 includes moresub-frames that can be used to transmit the MIB. As such, when the BS102 uses the frame structure of the anchor carrier 410 of FIG. 4 totransmit the MIB, the UE 104 may responsively spend more time decodingthe MIB; and when the BS 102 uses the frame structure of the anchorcarrier 510 of FIG. 5 to transmit the MIB, the UE 104 may responsivelyspend less time decoding the MIB. In some embodiments, based on therespective decoding requirements, the BS 102 may determine which of theframe structures between 410 and 510 for the use of transmitting theMIB. As a choice, the UE 104 may blindly decode which of thesub-frames(s) in the 410 or 510 have been used to transmit the MIB.

In accordance with the illustrated embodiment of FIG. 5 , the SSS,transmitted using the anchor carrier 510 on a respective frequencylocation (not shown), may indicate the frequency location of thenon-anchor carrier 530 by selecting one from a plurality of pre-definedfrequency location options, as discussed above with respect to FIGS. 3B,3C, and 3D. As such, after the UE 104 (FIG. 1 ) receives the SSS that istransmitted on the anchor carrier 510, the UE 104 can know using whichfrequency location to receive the SIB1 that is transmitted on thenon-anchor carrier 530.

Further, in such an embodiment of using the SSS to indicate thefrequency location of the non-anchor carrier 530, the BS 102 may use thefrequency location of the non-anchor carrier 530 to determine a sequence“d(n)” of the SSS. Accordingly, the UE 104 may use the sequence d(n) ofthe SSS to estimate the indicated frequency location of the non-anchorcarrier 530. In particular, the UE may use the following equation of thesequence d(n) of the SSS to estimate the indicated frequency location ofthe non-anchor carrier 530.

${d(n)} = {{b_{q}(m)}e^{{- j}2\pi\theta_{f}n}e^{{- j}\frac{\pi\;{{un}^{\prime}{({n^{\prime} + 1})}}}{131}}}$n = 0, 1, …  , 131 n^(′) = n mod 131 m = n mod 128wherein  u = N_(ID)^(Ncell)mod 126 + 3$q = \left\lfloor \frac{N_{ID}^{Ncell}}{126} \right\rfloor$$\theta_{f} = {\frac{33}{132}i}$Further, N_(ID) ^(Ncell) represents a physical cell identity (e.g., avalue between 0˜503); b_(q)(m) represents a pre-defined sequence, whereq can be 1, 2, or 3; i represents an index of the plurality ofpre-defined frequency location options (e.g., 0, 1, 2, 3 in the currentexample).

FIG. 6 illustrates exemplary frame structures of an anchor carrier 610and a non-anchor carrier 630, respectively, in accordance with someembodiments of the present disclosure. Similarly, the anchor carrier 610and the non-anchor carrier 630 share the same carrier bandwidth “B”(e.g., 180 kHz) along the frequency domain. In some embodiments, theanchor carrier 610 and the non-anchor carrier 630 may occupy respectivedifferent frequency ranges. Alternatively stated, the anchor carrier 610and the non-anchor carrier 630 may be spaced from each other by one ormore carrier bandwidths B, which will be discussed in further detailbelow.

In the illustrated embodiment of FIG. 6 , the anchor carrier 610includes frames 610-1, 610-2, 610-3, and 610-4 coupled from one toanother along a time domain; and the non-anchor carrier 630 includesframes 630-1, 630-2, 630-3, and 630-4 coupled from one to another alongthe time domain. In some embodiments, each of the respective frames ofthe anchor carrier 610 and the non-anchor carrier 630 includes 10sub-frames, each of which is associated with a sub-frame index #, e.g.,0, 1, 2, 3, 4, 5, 6, 7, 8, or 9. Further, in the illustrated embodimentof FIG. 6 , the synchronization signals, including the PSS and the SSS,and part of the public signals, including the MIB, are transmitted onthe anchor carrier 610; and part of the public signals, including theSIB1, are transmitted on the non-anchor carrier 630.

More specifically, in some embodiments, the PSS is transmitted onsub-frame #5 of the frame 610-1, sub-frame #5 of the frame 610-2,sub-frame #5 of the frame 610-3, and sub-frame #5 of the frame 610-4;the SSS is transmitted on sub-frame #9 of the frame 610-1 and sub-frame#9 of the frame 610-3; and the MIB is transmitted on sub-frame #0 of theframe 610-1, sub-frame #0 of the frame 610-2, sub-frame #0 of the frame610-3, and sub-frame #0 of the frame 610-4. The SIB1 can be transmittedon sub-frame #4 of the frame 630-1, sub-frame #4 of the frame 630-2,sub-frame #4 of the frame 630-3, and sub-frame #4 of the frame 630-4.For clarity of illustration, the respective sub-frame(s) used totransmit the PSS, the SSS, the MIB, and the SIB1 are filled with adiagonal stripe pattern, a dotted pattern, a vertical stripe pattern,and a horizontal stripe pattern, respectively. It is noted that theanchor carrier 610 and the non-anchor carrier 630 may be used in theNB-IoT system utilizing a frequency domain duplex (FDD) transmissionmode.

In accordance with the illustrated embodiment of FIG. 6 , the MIB,transmitted using the anchor carrier 610 on a respective frequencylocation, may indicate the frequency location of the non-anchor carrier630 by selecting one from a plurality of pre-defined frequency locationoptions. As such, after the UE 104 (FIG. 1 ) receives and then read theMIB that is transmitted on the anchor carrier 610, the UE 104 can knowusing which frequency location to receive the SIB1 that is transmittedon the non-anchor carrier 630.

FIG. 7 illustrates exemplary frame structures of an anchor carrier 710and a non-anchor carrier 730 used to transmit the synchronizationsignals and public signals, respectively, in accordance with someembodiments of the present disclosure. Similarly, the anchor carrier 710and the non-anchor carrier 730 share the same carrier bandwidth “B”(e.g., 180 kHz) along the frequency domain. In some embodiments, theanchor carrier 710 and the non-anchor carrier 730 may occupy respectivedifferent frequency ranges. Alternatively stated, respective frequencylocations of the anchor carrier 710 and the non-anchor carrier 730 maybe spaced from each other by one or more carrier bandwidths B, whichwill be discussed in further detail below.

In the illustrated embodiment of FIG. 7 , the anchor carrier 710includes frames 710-1, 710-2, 710-3, and 710-4 coupled from one toanother along a time domain; and the non-anchor carrier 730 includesframes 730-1, 730-2, 730-3, and 730-4 coupled from one to another alongthe time domain. In some embodiments, each of the respective frames ofthe anchor carrier 710 and the non-anchor carrier 730 includes 10sub-frames, each of which is associated with a sub-frame index #, e.g.,0, 1, 2, 3, 4, 5, 6, 7, 8, or 9. Further, in the illustrated embodimentof FIG. 7 , the synchronization signals, including the PSS and the SSS,are transmitted on the anchor carrier 710; and the public signals,including the MIB and SIB1, are transmitted on the non-anchor carrier730.

More specifically, in some embodiments, the PSS is transmitted onsub-frame #0 of the frame 710-1, sub-frame #0 of the frame 710-2,sub-frame #0 of the frame 710-3, and sub-frame #0 of the frame 710-4;and the SSS is transmitted on sub-frame #5 of the frame 710-1. The MIBis transmitted on sub-frame #0 of the frame 730-1, and sub-frame #0 ofthe frame 730-3; and the SIB1 can be transmitted on sub-frame #5 of theframe 730-1, and sub-frame #5 of the frame 730-3. For clarity ofillustration, the respective sub-frame(s) used to transmit the PSS, theSSS, the MIB, and the SIB1 are filled with a diagonal stripe pattern, adotted pattern, a vertical stripe pattern, and a horizontal stripepattern, respectively. It is noted that the anchor carrier 710 and thenon-anchor carrier 730 may be used in the NB-IoT system utilizing theTDD transmission mode, which causes the sub-frames used by the MIB to berespectively aligned with at least part of the sub-frames used by thePSS along the time domain.

In accordance with the illustrated embodiment of FIG. 7 , neither thePSS nor the SSS, transmitted using the anchor carrier 710 on arespective frequency location (not shown), indicates the frequencylocation of the non-anchor carrier 730. Instead, the frequency locationof the non-anchor carrier 730 with respect to the frequency location ofthe anchor carrier 710 may be pre-defined by the above-mentionedprotocol of the NB-IoT system. For example, when the NB-IoT systemoperates under the standalone mode, the frequency location of thenon-anchor carrier 730 may be pre-defined to be positively or negativelyspaced apart from the frequency location of the anchor carrier 710 by 1carrier bandwidth (i.e., 1×B or −1×B); and when the NB-IoT systemoperates under the non-standalone mode, the frequency location of thenon-anchor carrier 730 may be pre-defined to be positively or negativelyspaced apart from the frequency location of the anchor carrier 710 by 6carrier bandwidths (i.e., 6×B or −6×B).

FIG. 8 illustrates exemplary frame structures of an anchor carrier 810and a non-anchor carrier 830 used to transmit the synchronizationsignals and public signals, respectively, in accordance with someembodiments of the present disclosure. Similarly, the anchor carrier 810and the non-anchor carrier 830 share the same carrier bandwidth “B”(e.g., 180 kHz) along the frequency domain. In some embodiments, theanchor carrier 810 and the non-anchor carrier 830 may occupy respectivedifferent frequency ranges. Alternatively stated, respective frequencylocations of the anchor carrier 810 and the non-anchor carrier 830 maybe spaced from each other by one or more carrier bandwidths B, whichwill be discussed in further detail below.

In the illustrated embodiment of FIG. 8 , the anchor carrier 810includes frames 810-1, 810-2, 810-3, and 810-4 coupled from one toanother along a time domain; and the non-anchor carrier 830 includesframes 830-1, 830-2, 830-3, and 830-4 coupled from one to another alongthe time domain. In some embodiments, each of the respective frames ofthe anchor carrier 810 and the non-anchor carrier 830 includes 10sub-frames, each of which is associated with a sub-frame index #, e.g.,0, 1, 2, 3, 4, 5, 6, 7, 8, or 9. Further, in the illustrated embodimentof FIG. 8 , the synchronization signals, including the PSS and the SSS,are transmitted on the anchor carrier 810; and the public signals,including the MIB and SIB1, are transmitted on the non-anchor carrier830.

More specifically, in some embodiments, the PSS is transmitted onsub-frame #0 of the frame 810-1, sub-frame #0 of the frame 810-2,sub-frame #0 of the frame 810-3, and sub-frame #0 of the frame 810-4;and the SSS is transmitted on sub-frame #5 of the frame 810-1 andsub-frame #5 of the frame 810-3. The MIB is transmitted on sub-frame #0of the frame 830-1, sub-frame #0 of the frame 830-2, sub-frame #0 of theframe 830-3, and sub-frame #0 of the frame 830-4; and the SIB1 can betransmitted on sub-frame #5 of the frame 830-1, sub-frame #5 of theframe 830-2, sub-frame #5 of the frame 830-3, and sub-frame #5 of theframe 830-4. For clarity of illustration, the respective sub-frame(s)used to transmit the PSS, the SSS, the MIB, and the SIB1 are filled witha diagonal stripe pattern, a dotted pattern, a vertical stripe pattern,and a horizontal stripe pattern, respectively. It is noted that theanchor carrier 810 and the non-anchor carrier 830 may be used in theNB-IoT system utilizing the TDD transmission mode, which causes thesub-frames used by the MIB to be respectively aligned with at least partof the sub-frames used by the PSS along the time domain.

When compared to the frame structure of the non-anchor carrier 730 ofFIG. 7 , the frame structure of the non-anchor carrier 830 of FIG. 8includes more sub-frames that can be used to transmit the MIB. As such,when the BS 102 uses the frame structure of the non-anchor carrier 730of FIG. 7 to transmit the MIB, the UE 104 may responsively spend moretime decoding the MIB; and when the BS 102 uses the frame structure ofthe non-anchor carrier 830 of FIG. 8 to transmit the MIB, the UE 104 mayresponsively spend less time decoding the MIB. In some embodiments,based on the respective decoding requirements, the BS 102 may determinewhich of the frame structures between 730 and 830 for the use oftransmitting the MIB. As a choice, the UE 104 may blindly decode whichof the sub-frames(s) in the 730 or 830 have been used to transmit theMIB.

Further, when compared to the frame structure of the non-anchor carrier730 of FIG. 7 , the frame structure of the non-anchor carrier 830 ofFIG. 8 includes more sub-frames that can be used to transmit the SIB1.As such, when the BS 102 uses the frame structure of the non-anchorcarrier 830 of FIG. 8 to transmit the SIB1, the UE 104 may responsivelyspend less time decoding the SIB1; and when the BS 102 uses the framestructure of the non-anchor carrier 730 of FIG. 7 to transmit the SIB1,the UE 104 may responsively spend more time decoding the SIB1. In someembodiments, based on the respective decoding requirements, the BS 102may determine which of the frame structures between 730 and 830 for theuse of transmitting the SIB1. As a choice, the BS 102 may use the MIB toindicate which sub-frame(s) in the non-anchor carrier (730 or 830) hasbeen used to transmit the SIB1. For example, the MIB uses how many timesthe SIB1 is going to be repeatedly transmitted within a schedulingperiod to implicitly indicate which sub-frame(s) will be used totransmit the SIB1. In particular, when a number of times falls into afirst subset, the SIB1 is going to be transmitted using the sub-framesas shown in FIG. 7 ; and when the number of times falls into a secondsubset, the SIB1 is going to be transmitted using the sub-frames asshown in FIG. 8 .

In accordance with the illustrated embodiment of FIG. 8 , the SSS,transmitted using the anchor carrier 810 on a respective frequencylocation (not shown), may indicate the frequency location of thenon-anchor carrier 830 by selecting one from a plurality of pre-definedfrequency location options, as discussed above with respect to FIGS. 3B,3C, and 3D. As such, after the UE 104 (FIG. 1 ) receives the SSS that istransmitted on the anchor carrier 810, the UE 104 can know using whichfrequency location to receive the SIB1 that is transmitted on thenon-anchor carrier 830.

Further, in such an embodiment of using the SSS to indicate thefrequency location of the non-anchor carrier 830, the BS 102 may use thefrequency location of the non-anchor carrier 830 to determine a sequence“d(n)” of the SSS. Accordingly, the UE 104 may use the sequence d(n) ofthe SSS to estimate the indicated frequency location of the non-anchorcarrier 830. In particular, the UE may use the following equation of thesequence d(n) of the SSS to estimate the indicated frequency location ofthe non-anchor carrier 830.

${d(n)} = {{b_{q}(m)}e^{{- j}2\pi\theta_{f}n}e^{{- j}\frac{\pi\;{{un}^{\prime}{({n^{\prime} + 1})}}}{131}}}$n = 0, 1, …  , 131 n^(′) = n mod 131 m = n mod 128wherein  u = N_(ID)^(Ncell)mod 126 + 3$q = \left\lfloor \frac{N_{ID}^{Ncell}}{126} \right\rfloor$$\theta_{f} = {\frac{33}{132}i}$Further, N_(ID) ^(Ncell) represents a physical cell identity (e.g., avalue between 0˜503); b_(q)(m) represents a pre-defined sequence, whereq can be 1, 2, or 3; i represents an index of the plurality ofpre-defined frequency location options (e.g., 0, 1, 2, 3 in the currentexample).

FIG. 9 illustrates exemplary frame structures of an anchor carrier 910and a non-anchor carrier 930 used to transmit the synchronizationsignals and public signals, respectively, in accordance with someembodiments of the present disclosure. Similarly, the anchor carrier 910and the non-anchor carrier 930 share the same carrier bandwidth “B”(e.g., 180 kHz) along the frequency domain. In some embodiments, theanchor carrier 910 and the non-anchor carrier 930 may occupy respectivedifferent frequency ranges. Alternatively stated, respective frequencylocations of the anchor carrier 910 and the non-anchor carrier 930 maybe spaced from each other by one or more carrier bandwidths B, whichwill be discussed in further detail below.

In the illustrated embodiment of FIG. 9 , the anchor carrier 910includes frames 910-1, 910-2, 910-3, and 910-4 coupled from one toanother along a time domain; and the non-anchor carrier 830 includesframes 930-1, 930-2, 930-3, and 930-4 coupled from one to another alongthe time domain. In some embodiments, each of the respective frames ofthe anchor carrier 910 and the non-anchor carrier 930 includes 10sub-frames, each of which is associated with a sub-frame index #, e.g.,0, 1, 2, 3, 4, 5, 6, 7, 8, or 9. Further, in the illustrated embodimentof FIG. 9 , the synchronization signals, including the PSS and the SSS,are transmitted on the anchor carrier 910; and the public signals,including the MIB and SIB1, are transmitted on the non-anchor carrier930.

More specifically, in some embodiments, the PSS is transmitted onsub-frame #5 of the frame 910-1, sub-frame #5 of the frame 910-2,sub-frame #5 of the frame 910-3, and sub-frame #5 of the frame 910-4;and the SSS is transmitted on sub-frame #9 of the frame 910-2 andsub-frame #9 of the frame 910-3. The MIB is transmitted on sub-frame #0of the frame 930-1, sub-frame #0 of the frame 930-2, sub-frame #0 of theframe 930-3, and sub-frame #0 of the frame 930-4; and the SIB1 can betransmitted on sub-frame #4 of the frame 930-1, sub-frame #4 of theframe 930-2, sub-frame #4 of the frame 930-3, and sub-frame #4 of theframe 930-4. For clarity of illustration, the respective sub-frame(s)used to transmit the PSS, the SSS, the MIB, and the SIB1 are filled witha diagonal stripe pattern, a dotted pattern, a vertical stripe pattern,and a horizontal stripe pattern, respectively. It is noted that theanchor carrier 910 and the non-anchor carrier 930 may be used in theNB-IoT system utilizing the FDD transmission mode.

In accordance with the illustrated embodiment of FIG. 9 , the SSS,transmitted using the anchor carrier 910 on a respective frequencylocation (not shown), may indicate the frequency location of thenon-anchor carrier 930 by selecting one from a plurality of pre-definedfrequency location options, as discussed above with respect to FIGS. 3B,3C, and 3D. As such, after the UE 104 (FIG. 1 ) receives the SSS that istransmitted on the anchor carrier 910, the UE 104 can know using whichfrequency location to receive the SIB1 that is transmitted on thenon-anchor carrier 930.

Further, in such an embodiment of using the SSS to indicate thefrequency location of the non-anchor carrier 930, the BS 102 may use thefrequency location of the non-anchor carrier 930 to determine a sequence“d(n)” of the SSS. Accordingly, the UE 104 may use the sequence d(n) ofthe SSS to estimate the indicated frequency location of the non-anchorcarrier 930. In particular, the UE may use the following equation of thesequence d(n) of the SSS to estimate the indicated frequency location ofthe non-anchor carrier 930.

${d(n)} = {{b_{q}(m)}e^{{- j}2\pi\theta_{f}n}e^{{- j}\frac{\pi\;{{un}^{\prime}{({n^{\prime} + 1})}}}{131}}}$n = 0, 1, …  , 131 n^(′) = n mod 131 m = n mod 128wherein  u = N_(ID)^(Ncell)mod 126 + 3$q = \left\lfloor \frac{N_{ID}^{Ncell}}{126} \right\rfloor$$\theta_{f} = {\frac{33}{132}i}$Further, N_(ID) ^(Ncell) represents a physical cell identity (e.g., avalue between 0˜503); b_(q)(m) represents a pre-defined sequence, whereq can be 1, 2, or 3; i represents an index of the plurality ofpre-defined frequency location options (e.g., 0, 1, 2, 3 in the currentexample).

Further, in accordance with some embodiments, which sub-frame(s) beingused to transmit the SIB1 are determined by a Physical Cell Identity(PCID) and how many times the SIB1 is going to be repeatedly transmittedwithin a scheduling period as indicated by the MIB. In an example wheresub-frame #5 of the frame 830-1, sub-frame #5 of the frame 830-2,sub-frame #5 of the frame 830-3, and sub-frame #5 of the frame 830-4 canbe used to transmit the SIB1 (as shown in FIG. 8 ), a scheduling periodspans across 256 frames (i.e., 256 sub-frames in a scheduling period canbe used to transmit the SIB1) and one transmission of the SIB1 in ascheduling period consumes 8 sub-frames, a maximum number of the times(to repeatedly transmit the SIB1) within such a period is 32. When theMIB indicates that the SIB1 will be repeatedly transmitted 32 times in ascheduling period, sub-frame #5 of the frame 830-1, sub-frame #5 of theframe 830-2, sub-frame #5 of the frame 830-3, and sub-frame #5 of theframe 830-4 are then determined as being used to transmit the SIB1; andwhen the MIB indicates that the SIB1 will be repeatedly transmitted 16times, the sub-frames, determined as being used to transmit the SIB1,are sub-frame #5 of the frame 830-1 and sub-frame #5 of the frame 830-3for an odd PCID or sub-frame #5 of the frame 830-2 and sub-frame #5 ofthe frame 830-4 for an even PCID.

While various embodiments of the invention have been described above, itshould be understood that they have been presented by way of exampleonly, and not by way of limitation. Likewise, the various diagrams maydepict an example architectural or configuration, which are provided toenable persons of ordinary skill in the art to understand exemplaryfeatures and functions of the invention. Such persons would understand,however, that the invention is not restricted to the illustrated examplearchitectures or configurations, but can be implemented using a varietyof alternative architectures and configurations. Additionally, as wouldbe understood by persons of ordinary skill in the art, one or morefeatures of one embodiment can be combined with one or more features ofanother embodiment described herein. Thus, the breadth and scope of thepresent disclosure should not be limited by any of the above-describedexemplary embodiments.

It is also understood that any reference to an element herein using adesignation such as “first,” “second,” and so forth does not generallylimit the quantity or order of those elements. Rather, thesedesignations can be used herein as a convenient means of distinguishingbetween two or more elements or instances of an element. Thus, areference to first and second elements does not mean that only twoelements can be employed, or that the first element must precede thesecond element in some manner.

Additionally, a person having ordinary skill in the art would understandthat information and signals can be represented using any of a varietyof different technologies and techniques. For example, data,instructions, commands, information, signals, bits and symbols, forexample, which may be referenced in the above description can berepresented by voltages, currents, electromagnetic waves, magneticfields or particles, optical fields or particles, or any combinationthereof.

A person of ordinary skill in the art would further appreciate that anyof the various illustrative logical blocks, modules, processors, means,circuits, methods and functions described in connection with the aspectsdisclosed herein can be implemented by electronic hardware (e.g., adigital implementation, an analog implementation, or a combination ofthe two), firmware, various forms of program or design codeincorporating instructions (which can be referred to herein, forconvenience, as “software” or a “software module), or any combination ofthese techniques. To clearly illustrate this interchangeability ofhardware, firmware and software, various illustrative components,blocks, modules, circuits, and steps have been described above generallyin terms of their functionality. Whether such functionality isimplemented as hardware, firmware or software, or a combination of thesetechniques, depends upon the particular application and designconstraints imposed on the overall system. Skilled artisans canimplement the described functionality in various ways for eachparticular application, but such implementation decisions do not cause adeparture from the scope of the present disclosure.

Furthermore, a person of ordinary skill in the art would understand thatvarious illustrative logical blocks, modules, devices, components andcircuits described herein can be implemented within or performed by anintegrated circuit (IC) that can include a general purpose processor, adigital signal processor (DSP), an application specific integratedcircuit (ASIC), a field programmable gate array (FPGA) or otherprogrammable logic device, or any combination thereof. The logicalblocks, modules, and circuits can further include antennas and/ortransceivers to communicate with various components within the networkor within the device. A general purpose processor can be amicroprocessor, but in the alternative, the processor can be anyconventional processor, controller, or state machine. A processor canalso be implemented as a combination of computing devices, e.g., acombination of a DSP and a microprocessor, a plurality ofmicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other suitable configuration to perform the functionsdescribed herein.

If implemented in software, the functions can be stored as one or moreinstructions or code on a computer-readable medium. Thus, the steps of amethod or algorithm disclosed herein can be implemented as softwarestored on a computer-readable medium. Computer-readable media includesboth computer storage media and communication media including any mediumthat can be enabled to transfer a computer program or code from oneplace to another. A storage media can be any available media that can beaccessed by a computer. By way of example, and not limitation, suchcomputer-readable media can include RAM, ROM, EEPROM, CD-ROM or otheroptical disk storage, magnetic disk storage or other magnetic storagedevices, or any other medium that can be used to store desired programcode in the form of instructions or data structures and that can beaccessed by a computer.

In this document, the term “module” as used herein, refers to software,firmware, hardware, and any combination of these elements for performingthe associated functions described herein. Additionally, for purpose ofdiscussion, the various modules are described as discrete modules;however, as would be apparent to one of ordinary skill in the art, twoor more modules may be combined to form a single module that performsthe associated functions according embodiments of the invention.

Additionally, memory or other storage, as well as communicationcomponents, may be employed in embodiments of the invention. It will beappreciated that, for clarity purposes, the above description hasdescribed embodiments of the invention with reference to differentfunctional units and processors. However, it will be apparent that anysuitable distribution of functionality between different functionalunits, processing logic elements or domains may be used withoutdetracting from the invention. For example, functionality illustrated tobe performed by separate processing logic elements, or controllers, maybe performed by the same processing logic element, or controller. Hence,references to specific functional units are only references to asuitable means for providing the described functionality, rather thanindicative of a strict logical or physical structure or organization.

Various modifications to the implementations described in thisdisclosure will be readily apparent to those skilled in the art, and thegeneral principles defined herein can be applied to otherimplementations without departing from the scope of this disclosure.Thus, the disclosure is not intended to be limited to theimplementations shown herein, but is to be accorded the widest scopeconsistent with the novel features and principles disclosed herein, asrecited in the claims below.

What is claimed is:
 1. A method, comprising: transmitting a primarysynchronization signal and a secondary synchronization signal using ananchor carrier with a first frequency location; and transmitting asystem information block using a non-anchor carrier with a secondfrequency location different from the first frequency location, whereina master information block is also transmitted using the anchor carrier,and wherein the master information block indicates one from a pluralityof options of the second frequency location of the non-anchor carrier,wherein the plurality of options of the second frequency locationcomprises a first carrier spacing from the first frequency location whenoperated in a standalone mode and a second carrier spacing from thefirst frequency location, different from the first carrier spacing whenoperated in a non-standalone mode.
 2. The method of claim 1, furthercomprising: determining a sequence of the secondary synchronizationsignal based on at least one of the plurality of options, wherein thesecond frequency location of the non-anchor carrier is pre-defined andis different from the first frequency location.
 3. The method of claim1, wherein each of the plurality of options of the second frequencylocation of the non-anchor carrier defines the respective secondfrequency location as being spaced from the first frequency location ofthe anchor carrier by singular or plural carrier bandwidths of theanchor carrier.
 4. The method of claim 1, wherein the secondarysynchronization signal, transmitted using the anchor carrier, indicatesone from the plurality of options of the second frequency location ofthe non-anchor carrier.
 5. The method of claim 4, determining a sequenceof the secondary synchronization signal based on the indicated secondfrequency location of the non-anchor carrier.
 6. A method, comprising:receiving a primary synchronization signal and a secondarysynchronization signal modulated on an anchor carrier with a firstfrequency location; receiving a system information block modulated on anon-anchor carrier with a second frequency location different from thefirst frequency location, wherein a master information block is alsotransmitted using the anchor carrier, and wherein the master informationblock indicates one from a plurality of options of the second frequencylocation of the non-anchor carrier, wherein the plurality of options ofthe second frequency location comprises a first carrier spacing from thefirst frequency location when operated in a standalone mode and a secondcarrier spacing from the first frequency location, different from thefirst carrier spacing when operated in a non-standalone mode.
 7. Themethod of claim 6, further comprising: determining the second frequencylocation of the non-anchor carrier based on a sequence of the secondarysynchronization signal, wherein the second frequency location of thenon-anchor carrier is pre-defined and is different from the firstfrequency location.
 8. The method of claim 6, wherein each of theplurality of options of the second frequency location of the non-anchorcarrier defines the respective second frequency location as being spacedfrom the first frequency location of the anchor carrier by singular orplural carrier bandwidths of the anchor carrier.
 9. The method of claim6, wherein the secondary synchronization signal, transmitted using theanchor carrier, indicates one from the plurality of options of thesecond frequency location of the non-anchor carrier.
 10. The method ofclaim 9, further comprising estimating the indicated second frequencylocation of the non-anchor carrier based on a sequence of the secondarysynchronization signal.
 11. A communication node, comprising: atransmitter configured to: transmit a primary synchronization signal anda secondary synchronization signal using an anchor carrier with a firstfrequency location; and transmit a system information block using anon-anchor carrier with a second frequency location different from thefirst frequency location, wherein a master information block is alsotransmitted using the anchor carrier, and wherein the master informationblock indicates one from a plurality of options of the second frequencylocation of the non-anchor carrier, wherein the plurality of options ofthe second frequency location comprises a first carrier spacing from thefirst frequency location when operated in a standalone mode and a secondcarrier spacing from the first frequency location, different from thefirst carrier spacing, when operated in a non-standalone mode.
 12. Thecommunication node of claim 11, further comprising: at least oneprocessor, coupled to the transmitter, and configured to determine asequence of the secondary synchronization signal based on at least oneof the plurality of options, wherein the second frequency location ofthe non-anchor carrier is pre-defined and is different from the firstfrequency location.
 13. The communication node of claim 12, wherein eachof the plurality of options of the second frequency location of thenon-anchor carrier defines the respective second frequency location asbeing spaced from the first frequency location of the anchor carrier bysingular or plural carrier bandwidths of the anchor carrier.
 14. Thecommunication node of claim 12, wherein the secondary synchronizationsignal, transmitted using the anchor carrier, indicates one from theplurality of options of the second frequency location of the non-anchorcarrier.
 15. The communication node of claim 14, wherein the at leastone processor is further configured to determine a sequence of thesecondary synchronization signal based on the indicated second frequencylocation of the non-anchor carrier.
 16. A communication device,comprising: a receiver configured to: receive a primary synchronizationsignal and a secondary synchronization signal modulated on an anchorcarrier with a first frequency location; and receive a systeminformation block modulated on a non-anchor carrier with a secondfrequency location different from the first frequency location, whereina master information block is also transmitted using the anchor carrier,and wherein the master information block indicates one from a pluralityof options of the second frequency location of the non-anchor carrier,wherein the plurality of options of the second frequency locationcomprises a first carrier spacing from the first frequency location whenoperated in a standalone mode and a second carrier spacing from thefirst frequency location, different from the first carrier spacing, whenoperated in a non-standalone mode.
 17. The communication device of claim16, further comprising: at least one processor, coupled to the receiver,and configured to determine the second frequency location of thenon-anchor carrier based on a sequence of the secondary synchronizationsignal, wherein the second frequency location of the non-anchor carrieris pre-defined and is different from the first frequency location. 18.The communication device of claim 17, wherein each of the plurality ofoptions of the second frequency location of the non-anchor carrierdefines the respective second frequency location as being spaced fromthe first frequency location of the anchor carrier by singular or pluralcarrier bandwidths of the anchor carrier.
 19. The communication deviceof claim 17, wherein the secondary synchronization signal, transmittedusing the anchor carrier, indicates one from the plurality of options ofthe second frequency location of the non-anchor carrier.
 20. Thecommunication device of claim 19, wherein the at least one processor isfurther configured to estimate the indicated second frequency locationof the non-anchor carrier based on a sequence of the secondarysynchronization signal.